Jacob Perkins

Jacob Perkins was born in Newburyport, Massachusetts, on July 9, 1766, and apprenticed to a goldsmith at twelve. He never received a formal scientific education and spent his life as a working inventor of the pre-professional kind: by twenty-one he was making dies for the Massachusetts state coinage, and he went on to develop a nail-making machine, a pioneering method of steel-plate engraving for banknotes, and a pressure-based depth gauge. He held more than twenty American and nineteen British patents.

In 1819 he moved to London, chasing a Bank of England contract for anti-counterfeiting banknote engraving. He did not win it outright, but the firm he founded, Perkins Bacon, went on to print the Penny Black — the world's first adhesive postage stamp. London also gave him room for his obsession with high-pressure steam. He built experimental boilers running at pressures other engineers considered suicidal, and a steam gun that fired projectiles by pressure alone; the Duke of Wellington watched a demonstration in 1825 and declined to arm the British Army with it.

His enduring work came almost as an afterthought. In August 1834, at sixty-eight, Perkins was granted British patent No. 6662, describing a closed cycle in which a volatile fluid — he used ether — is compressed, condensed, throttled through a valve, and evaporated again, absorbing heat as it boils. His mechanic John Hague built the machine, and it produced a small quantity of ice. This is the vapour-compression cycle, and it is the cycle running in every refrigerator, freezer, air conditioner, and heat pump on Earth today.

He did nothing with it. Perkins never commercialised the machine, the patent lapsed into obscurity, and ice continued to reach London by ship from Norway and the frozen lakes of New England. He died in London on July 30, 1849, remembered as a steam engineer. It took roughly ninety years for his refrigerator to reach an ordinary kitchen — and when it did, it arrived permanently: there are now more than two billion of them, running Perkins's loop essentially unchanged.